This invention is directed to wrenches and more particularly to open-end and box end wrenches, adjustable and non-adjustable as well as ratchet type and spanner wrenches. A draw back to end wrenches, both open and closed end is the tendency of the wrench to slip off of the head of the nut or bolt during adjustment. This tendency is especially critical when the wrench is in an odd position or the person using the wrench is positioned awkwardly and has difficulty in reaching the nut or bolt. The user of the wrench is often times given to fumbling with an index finger or use of the other hand to position the head of the wrench while turning the wrench and nut.
A number of prior art references have attempted to solve this problem. For example, U.S. Pat. No. 4,738,168 utilizes a retaining apparatus mounted in the wrench head for holding the nut or bolt in place. The retaining apparatus is secured within the head of the wrench, particularly a box end open or closed end wrench, by small projections that extend approximately 0.003 of an inch into the interior region of the box wrench. The projections are positioned on each side of the wrench head so that the retaining apparatus can slide from one side of the head to the other within the head of the wrench. The difficulty with this wrench concept is that it cannot be used at an angle to the nut or bolt. Secondly, the projections are so small that wear would soon have the retainer lost. Further, the retainer is less than 0.006 inches smaller than the wrench mating surfaces and will have a tendency to bind in the head of the wrench so that its movement from one position to another is impaired.
U.S. Pat. No. 3,121,356 approaches the problem from another angle, in that it has slots built into the center of the wrench to accommodate a bolt and a web that extends to the outer edge of the wrench head, particularly, an open-end wrench, on which the wrench can rest on the top of a nut. The difficulty of this concept is that it requires a rather wide wrench end, and again, the wrench must be used in a flat position.
U.S. Pat. No. 1,764,990 approaches the problem from a different perspective, in that it provides dual webs on each edge of the wrench head, particularly an open-end wrench head, such that the web, in conjunction with the walls of the wrench for contact with the nut form a recess in which the nut fits. The difficulty with this approach is that, again, the wrench must be used in basically a parallel condition with the top of the nut or bolt head; and secondly, it is limited in the size of the nut or bolt that it can engage. For example, the larger "self-locking" nut could not be utilized with this device. A similar approach is found in U.S. Pat. No. 1,936,352. Also U.S. Pat. No. 3,242,775 at FIG. 13 discloses an over hanging section which is brought to bear upon a nut to be tightened down.
U.S. Pat. No. 3,324,748 discloses a "ratchet" device which has an annular ridge inside an elongated face "box end" wrench. This wrench is rather thick and again can only be used with the wrench being substantially parallel to the head of the nut or bolt. The wrench "ratchets" or slips on the nut when filled at an angle (see FIG. 4).